Structural shear load sensing pin

Abstract

A shear load sensing pin comprising a pin housing having a longitudinal bore therethrough and a strain sensing element disposed in the bore and extending around a complete circumference of an inside wall of the pin surrounding the bore. The strain sensing element extends substantially perpendicular to a longitudinal axis of the pin, so that shear loads can be measured from changes in resistance of the strain sensing element. The strain sensing element can be formed of one or several wires that are wrapped around the circumference of the inside wall of the pin.

What is claimed is: 
     
         1 . A shear load sensing pin comprising:
 a pin housing having a longitudinal bore therethrough;   a strain sensing element disposed in the bore and extending around an complete circumference of an inside wall of the pin housing surrounding the bore, the strain sensing element extending substantially perpendicular to a longitudinal axis of the pin.   
     
     
         2 . The shear load sensing pin according to  claim 1 , wherein the strain sensing element comprises at least one wire extending along a length of the strain sensing element so that the wire extends substantially perpendicular to a longitudinal axis of the pin. 
     
     
         3 . The shear load sensing pin according to  claim 2 , wherein the wire is arranged in a grid that extends along a length of the strain sensing element several times. 
     
     
         4 . The shear load sensing pin according to  claim 2 , wherein the strain sensing element is wrapped helically around the inner wall of the pin housing so that the strain sensing element extends around the circumference of the bore at least two times. 
     
     
         5 . The shear load sensing pin according to  claim 4 , wherein the wire is arranged in a grid that traverses a length of the strain sensing element several times. 
     
     
         6 . The shear load sensing pin according to  claim 2 , wherein the at least one wire is made of Constantin. 
     
     
         7 . The shear load sensing pin according to  claim 1 , wherein the strain sensing element is connected to a Wheatstone bridge circuit that measures changes in resistance of the sensor element. 
     
     
         8 . The shear load sensing pin according to  claim 2 , wherein the wire is applied to a foil that is attached to the inside wall of the pin.